A toner for developing an electrostatic image has toner particles containing a binder resin and a colorant. The toner particle has at least a core composed of a low-temperature softening substance, an inner layer enclosing the core, and an outer layer enclosing the core and the inner layer. The core, the inner layer, and the outer layer are constituted respectively of a material which is discriminable by staining with triruthenium tetroxide and triosmium tetroxide.
A graft resin having a structure of the formula (1) and having a number average molecular weight of 2,000 to 50,000, ##STR1## has excellent low-temperature moldability and exhibits an excellent shelf life against softening when stored at high temperatures, and an electrostatic charge developing toner containing the above graft resin as a binder exhibits excellent low-temperature fixing properties, developability and transferability without impairing the shelf life.
It is to easily form a fixed image, especially a full color image, that exhibits a small difference in gloss depending on the fixing conditions of the toner, is excellent in smoothness, exhibits small unevenness of gloss, and has high image quality and high reliability. A toner for developing a static image to be fixed by heat on a fixing substrate, wherein a fixed image has a gloss Gm of about 20% or more, and a maximum value of a degree of change Gs of the gloss per 1.degree. C. of a difference of a surface temperature within a range of about from 140 to 170.degree. C. of a fixing member as a heating and fixing unit is 1.8% or less per 1.degree. C.; and a developer for a static image and a process for producing an image using the toner are provided.
A toner for developing electrostatic images is formed from toner particles containing at least a binder resin, a colorant, and a wax. The binder resin comprises a vinyl polymer component and a polyester component. The binder resin contains 40-99 wt. % of a component A, 0-20 wt. % of a component B, and 0-60 wt. % of a component C, the components B and C providing totally 1-60 wt. % of the binder resin. The component A comprises low- and medium-molecular weight components having molecular weights of below 10.sup.6, and the component B comprises high-molecular weight components having molecular weights of at least 106, respectively, based on a chromatogram obtained by gel permeation chromatography of a tetrahydrofuran (THF)-soluble component of the binder resin, and the component C is a THF-insoluble component of the binder resin. The GPC chromatogram of the THF-soluble component of the binder resin exhibits a main peak in a molecular weight region of 3.times.10.sup.3 -5.times.10.sup.4. The toner particles have a shape factor SF-1 of 100-160 and a shape factor SF-2 of 100-140.
The present invention provides a toner that exhibits excellent low-temperature fixing properties, offset resistance, and has excellent storage stability in a developing machine. The toner has, in a DSC curve obtained by measuring the toner with differential scanning calorimeter, a glass transition temperature (Tg1) measured in a first scan of 50.0 to 70.0.degree. C. and a temperature difference (Tg1-Tg2) between the glass transition temperature (Tg1) measured in the first scan and a glass transition temperature (Tg2) measured in a second scan ranging from 3.0 to 20.0.degree. C.
The present invention provides a toner that exhibits excellent low-temperature fixing properties, offset resistance, and has excellent storage stability in a developing machine. The toner has, in a DSC curve obtained by measuring the toner with differential scanning calorimeter, a glass transition temperature (Tg1) measured in a first scan of 50.0 to 70.0.degree. C. and a temperature difference (Tg1-Tg2) between the glass transition temperature (Tg1) measured in the first scan and a glass transition temperature (Tg2) measured in a second scan ranging from 3.0 to 20.0.degree. C.
